1 /* 2 * Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 import java.util.concurrent.atomic.AtomicInteger; 27 import java.util.function.Supplier; 28 import org.testng.annotations.Test; 29 import static org.testng.Assert.*; 30 31 /** 32 * @test 33 * @run testng ThreadLocalSupplierTest 34 * @summary tests ThreadLocal.withInitial(<Supplier>). 35 * Adapted from java.lang.Basic functional test of ThreadLocal 36 * 37 * @author Jim Gish <jim.gish@oracle.com> 38 */ 39 @Test 40 public class ThreadLocalSupplierTest { 41 42 static final class IntegerSupplier implements Supplier<Integer> { 43 44 private final AtomicInteger supply = new AtomicInteger(0); 45 46 @Override 47 public Integer get() { 48 return supply.getAndIncrement(); 49 } 50 51 public int numCalls() { 52 return supply.intValue(); 53 } 54 } 55 56 static IntegerSupplier theSupply = new IntegerSupplier(); 57 58 static final class MyThreadLocal extends ThreadLocal<Integer> { 59 60 private final ThreadLocal<Integer> delegate; 61 62 public volatile boolean everCalled; 63 64 public MyThreadLocal(Supplier<Integer> supplier) { 65 delegate = ThreadLocal.<Integer>withInitial(supplier); 66 } 67 68 @Override 69 public Integer get() { 70 return delegate.get(); 71 } 72 73 @Override 74 protected synchronized Integer initialValue() { 75 // this should never be called since we are using the factory instead 76 everCalled = true; 77 return null; 78 } 79 } 80 81 /** 82 * Our one and only ThreadLocal from which we get thread ids using a 83 * supplier which simply increments a counter on each call of get(). 84 */ 85 static MyThreadLocal threadLocal = new MyThreadLocal(theSupply); 86 87 public void testMultiThread() throws Exception { 88 final int threadCount = 500; 89 final Thread th[] = new Thread[threadCount]; 90 final boolean visited[] = new boolean[threadCount]; 91 92 // Create and start the threads 93 for (int i = 0; i < threadCount; i++) { 94 th[i] = new Thread() { 95 @Override 96 public void run() { 97 final int threadId = threadLocal.get(); 98 assertFalse(visited[threadId], "visited[" + threadId + "]=" + visited[threadId]); 99 visited[threadId] = true; 100 // check the get() again 101 final int secondCheckThreadId = threadLocal.get(); 102 assertEquals(secondCheckThreadId, threadId); 103 } 104 }; 105 th[i].start(); 106 } 107 108 // Wait for the threads to finish 109 for (int i = 0; i < threadCount; i++) { 110 th[i].join(); 111 } 112 113 assertEquals(theSupply.numCalls(), threadCount); 114 // make sure the provided initialValue() has not been called 115 assertFalse(threadLocal.everCalled); 116 // Check results 117 for (int i = 0; i < threadCount; i++) { 118 assertTrue(visited[i], "visited[" + i + "]=" + visited[i]); 119 } 120 } 121 122 public void testSimple() { 123 final String expected = "OneWithEverything"; 124 final ThreadLocal<String> threadLocal = ThreadLocal.<String>withInitial(() -> expected); 125 assertEquals(expected, threadLocal.get()); 126 } 127 }